XR274HR-10 in 318

Garrett Ellison said
Instead of milling the intake, your machinist should be milling the intake side of your cylinder heads, but the end rails of the intake will probably need milled too. I got to checking and the .050 comes closer to reducing the chamber volume closer to 53 cc's, so plan ahead on your compression before having them milled.
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Best idea. I had the heads milled and I bolted them on and the stock intake wouldn't fit. Instead of pulling the heads again I just machined the intake. Now the heads and intake will have to be used together. No worries though. I don't plan on any changes and some time in the engines history one head was replaced.